I'll just assume that's a bizarre bug with the combination of mods I have installed. Same with the awkward skybox and camera spinning while on the boat...
You can get some fantastic prizes from Chocobo Hot & Cold - Protect Ring and Robe of Lords are two of the best items in the game - but it requires copious amounts of grinding that irritating minigame. Thankfully if you use the speed up feature in the HD ports the timer still runs at the same speed so the process goes much faster; you can consistently hit 8 prizes dug up for the max bonus and get 100+ points per run.
There's also several more Chocographs to uncover but I was just interested in the second one as it's the only other one whose prize we can collect at the moment.
This one contains 5 Potions, 5 Hi-potions, 2 Tents and 2 Cotton Robes. Nothing incredible but still worth getting.